1. Field of the Invention
The present invention relates to a human gp130 protein, which is a protein participating in the transmission of an IL-6 signal, a DNA coding for this protein, and a means for and a method of producing this protein by genetic engineering.
2. Description of the Related Art
Interleukin-6 (IL-6) is a protein participating broadly in the proliferation and differentiation of an organism, and is characterized in that the protein plays an important role in defense system of an organism such as immunity, hematopoiesis or inflammation (see Kishimoto, Blood, 74, page 1, 1989). It is reported that an abnormal production of IL-6 may become a factor in the cause of various autoimmune diseases (see Kishimoto and Hirano, Ann. Rev. Immunol., page 485, 1988).
The inventors isolated a gene for human IL-6 receptor on the cell membrane, which is specifically bonded to human IL-6, and determined the primary structure thereof (see Japanese Patent Application No. 63-194885). Then the inventors isolated a gene of mouse IL-6 receptor on the cell membrane, which is specifically bonded to mouse IL-6, and determined the primary structure thereof (see Japanese Patent Application No. 1-292230). Furthermore, the inventors prepared a soluble IL-6 receptor (extracellular portion of an IL-6 receptor), considered to be usable for a therapeutic or diagnostic medicine, from the human IL-6 receptor gene as the starting material (see Japanese Patent Application No. 1-9774).